William mitnroe



UNITED STATES PATENT OFFICE.

\VILLIAM MUNROE, OF NEW' YORK, N. Y.

UPRlGHT-PIANO ACTION.

SPECIFICATION forming part of Letters Patent No. 551,832, dated December24, 1895.

Application filed April 23,1895. Serial No. 546,890. (No model.)

To all whom, it may concern.-

Be it known that I, IVILLIAM MUNROE, of the city, county, an d State ofNew York, have invented an Improved Upright-Piano Action, of which thefollowing is a full, clear, and exact description, reference being hadto the accompanying drawings, making part of this Specification, inwhich- Figure 1 is a perspective view of an uprightpiano actionconstructed in accordance with my present invention, the several partsbeing in their normal positioni. 6., with the hammer, jack and key-leverat rest. Fig. 2 is a side elevation representing the key depressed andthe hammer-rod in its upright position immediately after the recessionof the hammer from the string; Fig. 3, a transverse vertical section(enlarged) on the line 10 w of Fig. 2, looking in the direction of thearrow 35 5 Fig. i, a similar section (enlarged) on the line 20 w of Fig.2, looking in the direction of the arrow 36; Fig. 5, a vertical sectiontaken in the direction of the line x a: of Figs. 3 and 4; Fig. 6, ahorizontal section (enlarged) on the line y y of Figs. 2 and 5; Fig. '7,a modification to be referred to.

My present invention relates to uprightpiano actions, and has for itsobjects to obtain elasticity of touch with prompt and rapid responses oftone and power of stroke by the employment of a minimum number of partsof simplest construction which permanently retain their effectivenessunder the various conditions of changes of temperature and oftransportation from place to place; and this invention consists, incombination with the jack and hammer, of certain springs of peculiarconstruction, arrangement and operation, by which I accomplish theaforesaid require ments so essential in instrumental practice, saidsprings and their related parts being hereinafter fully described andspecifically claimed.

In the said drawings, A represents the keylcver; B, the lifting-jack; C,the hammer; to, the hammer-rod; Z), the hammer-butt; c, a bifurcatedcleat screwed to the hammer-butt rail D, and to which cleat thehammer-butt is pivoted at 15 E is the hammer-rest rail provided with aninclined cushion d against which the upper end of the hammer-rod restswhen in its normal position-11. 6., when the key is not depressed andthe parts are in the position seen in Fig. 1. One of the strings isrepresented by the vertical line G.

H is the repeating-lever rail and I the escapement-rail. The key-leveris pivoted at e, and its outer or key end when depressed strikes acushion g secured to the transverse key-rail K thereunder, and the innerend of the key-lever is weighted at 15 and in its normal position restson a cushion 71. in a wellknown manner.

i is a rocker-cleat rigidly secured by adjusting-screws 16 to the top ofthe inner end of the key-lever and is provided with a socket 17 for thereception of the lower cushioned foot 18 of the upright lifting-rod Lpivoted at its upper end at 19 to a guide-lever M pivoted within abifurcated arm 20 projecting down from and secured to the under side ofthe hammer-butt rail D. This guide-lever M has a bifurcated standard Nrising from its upper side, to which is fulcrumed the bent foot 21 ofthe jack, between which and the guide-lever M is interposed a spiralspring 22 which is compressed when said lever and foot are raised andthe latter brought against the under side of the regulating-button 23 bythe ascent of the jack-lifting rod L when pressure is applied to depressthe key. This elastic button is made adjustable to limit the upwardmovement of the jack by a screw 24: passing through the eseapement-rail-I, and the upward and downward movements of said jack are insured andcontrolled by the guide-lever M.

A portion of the front of the hammer-butt, its lower front corner, and aportion of its contiguous lower side are provided with a cushion 76which is in constant contact with a shoulder l formed on thelifting-jack, the front upper portion of the cushion abutting againstthe contiguous surface of the jack when the upper end of the hammer-rodis resting against its cushion d and the keylever is at rest. Projectingfrom the rear of the hammer-butt is an offset 25, to the front of whichis secured an adjustable pad 1).

To the front of the jack, below the plane of its shoulder Z, is securedthe lower end of a small, flat, and nearly upright spring on of lightweight, the upper end of the spring being free and extending up to aboutthe level of the top of the jack, which is provided with a cushion n.This spring in its normal position has its upper end inclined forward(away) from the cushion, (see Fig. 1,) and in the position seen in Fig.2 when the key is depressed it is clamped and firmly held between thecushion n and the adjustable pad 1) secured to the offset 25. Thetension of the flat spring m increases as the pad 13 presses its freeend backward in the direction of the arrow when the jack ascends andtips the cushioned butt on the depression of the key.

The under side of the offset of the hammerbutt is provided with anelastic pad 26 which bears on the outer curved end 7 of a fiat andnearly horizontallyarranged spring P secured at 27 to a horizontalrepeating-lever Q fulcrumed at 28 to a bifurcated standard 29 risingfrom the repeating-lever rail H. The inner end of this lever Q isprovided with a cushion 30 on its under side which (like the cushion onthe hammerbutt) at all times rests on the shoulderZ of the jack. Also011 the under side of the lever Q is a cushion 31 which rests 011 therepeating-lever rail, and 011 the inner end of the lever Q is a cushion32 interposed between it and the under side of the spring P. There isalso a cushion 33 on the top of the hammer-butt rail D, the function ofthe several cushions or elastic pads being to afford a resilient rest orbearing for the parts contiguous thereto, and, while preventing loss ofmotion, insures easy gradual movement without tend ency to rattle. Aspiral spring 34: (see Fig. 7) may be substituted for the spring on andgood results be obtained thereby.

Operation: I will now describe the operation by which the function andrationale of the action of the springs m and P and their related deviceswill be clearly understood,

the parts being represented in their normal position of rest, as seen inFig. 1. \Vhen pressure is applied to depress the key, the jack israised, causing its shouldered portion Z to press upward and tip thecushioned hammer-butt away therefrom in the direction of the arrow 35,simultaneous with which the inner end of the repeating-lever Q is alsoraised by the jack and the inner curved end of the spring P is pressedupward against and tips forward the cushioned offset 25. WVhen thespring P is coming into this position and just before the foot 21 of thejack comes into contact with the regulating-button 23, the uppercushioned end of the jack advances toward the free end of the spring m,while at the same time the cushioned offset 25 moves inward to meet saidfree end, the result of which is that the shoulder Z of the jack. slidesslightly upward and laterally under the cushion 7a of the hammer-buttinto a position where the latter touches only the corner of the shoulderl, the top of the interposed spring on being at the same time clampedand held securely between the cushion n of the jack and pad 19 of thehammer-butt offset. Just before the clamping of the top of the spring onthe hammer strikes the string G, and on the completion of the downwardmovement of the key the hammer recedes to a position near the string,where it is ready to respond promptly to repeat its blow on the nextdownward stroke of the key. WVhen the pressure on the key is relaxed,the jack descends and its cushioned top recedes from and releases theupper end of the spring m, which then asserts itself and assists thejack to return its shoulder Zlaterally and slightly down ward into aposition under and to receive the cushioned hammer-butt. Otherwise thegravity of the jack would cause it to descend and carry its shoulderedseat away from the path of and out of contact with the pivoted11ammer-butt, which would result in objectionable noise and loss ofmotion incompatible with the ability to make quick repetition ofharmonious tones when the hammer is to be returned to continue itsstrokes on the string. hen the key-lever is at rest, the hammerrod issupported on the inclined cushion d,and the elastic pad 26 on the underside of the OH- set 25 rests its entire lower surface on the curvedouter end of the syiing P, while the cushion 7c of the hammer-butt fitssnugly upon the surface of the jack at its shoulder and also against theportions of the jack above and below it.

It will be understood from the foregoing that the spring P acts as anauxiliary aid or assistant to lighten the task of the spring m incarrying the shoulder of the jack under the hammer-butt, and by pressingupward on the offset of the butt relieves the jack of part of the weightof the hammer, thus insuring the production of prompt, loud, and rapidresponses.

I claim 1. The combination of the jack B with its cushion n, thehammer-butt offset with its elastic pad 19 and an interposed spring,substantially as set forth.

2. The repeating lever Q and hammer butt I), the lifting jack B with itsshoulder Z on which they both restthe hammer-butt offset 25 and thespring P having one end secured to said lever and its other endextending under the offset 25 and supporting a portion of the weight ofthe hammer, combined and arranged to operate as specified.

3. The jack B with its shoulder Z, the hammer O with its butt Z) restingthereon and periodically tipped thereby-the 11ammer-butt offset 25-thespring interposed and periodiand arranged to operate substantially asde- \Vitness my hand this 8th day-o1": April,

WILLIAM MUNROE. In presence of r. ALEXANDER HALLIDAY, THOMAS R. LEWIS.

